In order to identify nerve regeneration associated molecules, we have used a method called the differential display. We purified RNA from nerve injured-and normal hypoglossal nuclei respectively, and these RNAs were further processed for the differential display. The present method successfully demonstrated several candidate genes which were up-regulated after nerve injury. A screening using in situ hybridization histochemistry further squeeze the candidates. These are (1) molecules belonging to glutamate metabolism, (2) molecules implicated in free radical scavenger, (3) a certain group of growth factor receptors, (4) molecules along a certain intracellular signaling, and (5) molecules implicated in redox regulation. Since these molecules were derived from adult injured motoneurons which can survive even after nerve injury. We examined if these molecules were also respond to a similar type of nerve injury in new born motoneurons which were fated to die by nerve injury. Both adult and
… Morepups hypoglossal nerve were axotomized, and in situ hybridization was carried out to identify transcription regulations. In this comparison, we found that some molecules have an ability to respond to nerve injury in adult, but not in pups. For instance, LIF-R and GDNFR (alpha) respond to nerve injury positively in adult, but negatively in pups. This opposite responses to nerve injury may be a reason why adult motoneurons can survive and pup's motoneurons die after nerve injury.初年度の結果により、通常の成熟動物では、神経損傷に対して特定の遺伝子群が応答していることが明らかになた.それらは、(1)細胞外にあっては神経毒であるグルタミン酸の取り込みや代謝に関連した遺伝子群、(2)フリーラジカルのスカベンジャーシステムに関連した遺伝子群、(3)細胞内の酸化防止のための還元系分子、(4)特定の神経栄養因子受容体群、(5)一部のサイトカイン受容体分子、(6)神経成長因子/サイトカイン受容体の下流に存在する細胞内情報伝達関連分子、などであった.これらのうちのいくつかに関して幼若動物の神経損傷後に遺伝子発現を検討した.その結果、神経成長因子受容体のうちLIF受容体やGDBF受容体α鎖において、神経損傷後の発現が成熟動物と幼若動物で全く逆の応答を示すことが明らかになった.すなわち、損傷後神経が再生する系ではこれら受容体が著しく産生されるのに比べ、神経細胞死へ至る系では産生が抑制される.さらに、神経型のグルタミン酸トランスポーターであるEAAC1においても同様の結果が得られた.以上より神経が損傷後に生存するために必要な分子群の発現応答は個体発生の時期によってかなり異なり、それが損傷神経の運命を左右すると予想された. Less